A spun nonwoven fabric of this kind is known from JP A Patent 435 28 61, as a material for bags. The spun nonwoven fabric includes two types, A and B, of long conjugated multicomponent filaments. Filament type A comprises the polymer components (a1) and (a2), the latter having a melting point 30 degrees C. higher than (a1). Filament type B comprises the polymer components (b1) and (b2), component (b1) having a melting point 20 degrees C. higher than component (a1), and component (b2) having a melting point more than 30 degrees C. higher than component (b1).
The nonwoven fabric of JP A Patent 435 28 61 further possesses a four-layer structure in cross section, the individual layers differing in that the first contains only filaments of type A; the second layer and third layers contain filament types A and B, with a higher proportion of filament type A in the second and a higher proportion of filament type B in the third layer; while the subsequent fourth layer consists only of filaments of type B.
The different melting points on the two surfaces of the nonwoven fabric and the different melting points in the cross section of the nonwoven fabric which result from this configuration prevent delamination of the individual layers.